Airport capacity from takeoff assist

ABSTRACT

Systems and methods for ground-based aircraft thrust systems are provided. In particular, some embodiments use an electromechanical thrust assembly to accelerate aircraft using ground-based energy for takeoff. The assembly can include one or more sleds, one or more maglev tracks, and/or one or more linear motors. Airplanes are loaded onto a sled (e.g., a saddle-shaped sled) that supports and balances the airplane instead of the landing gear aboard the aircraft. The sled levitates above the ground using high-density permanent magnet arrays. Magnetic levitation forces are varied along the assembly to account for lift provided by airflow over the wings. An aircraft thrust system includes a magnetically levitated saddle-shaped sled with airbags that support an aircraft during takeoff acceleration coupled with a linear motor that spans the length of the distance needed for takeoff.

TECHNICAL FIELD

Various embodiments of the present invention generally relate to anelectromechanical thrust assembly. More specifically, variousembodiments of the present invention relate to systems and methods foran electromechanical thrust assembly, which can be used to accelerateaircraft using ground-based energy during takeoff.

BACKGROUND

To meet the demand for increased air travel, aircraft have become largerwith more mass, more engine power, larger wing spans and strongerlanding gear. This trend has led to longer (approximately 13,000 ft) andwider (approximately 200 ft) runways for the most recently designed longhaul aircraft—categorized as super jumbo jets. Wider runways allow forclearances to aircraft on adjacent runways or taxiways. Longer runwaysallow for longer takeoff runs and landings without requiring excessiveengine sizes but are limited in takeoff velocity by tire specifications.The larger airplanes require upgrades to pavement, taxi lanes andarrival lanes due to much larger weight and turning forces.

The largest airports in the most populated cities of the world face landconstraints where additional runways or longer runways require landacquisition or extending land into surrounding waters. Prior methods forextending civil airport capacity include adding additional runways atcurrent airports, adding additional airports in neighboring regions, orsome combination. The replacement of Stapleton airport near downtownDenver, Colo. with Denver International Airport to the north east ofDenver provides an example of prior airport design and abandonment formore-distant vacant land. Los Angeles International Airport is borderedby the Pacific Ocean to the west, dense housing to the north and south,and mixed-use land to the east. The Federal Aviation Authority in theUnited States of America has acquired many acres of land to the westbetween the airport and ocean, and to the north. Plans to expand theairport capacity by moving runways or adding runways to the north havenot overcome opposition to noise, pollution, and traffic congestion onroads leading to the airport. Heathrow Airport in London faces similaropposition to expansion.

New York's John F. Kennedy and LaGuardia airports border water andhighly populated regions making expansion difficult and expensive.Relocating these airports seems intractable given the size of the publictransportation structure that travelers use to access the airports. Evenif support transportation was easy to reconfigure, there is no landavailable in these highly populated areas that would offer improvedairport capacity. Expanding these two airports further into adjacentwaters offers additional land but at the expense of environmental andwaterway concerns. Proposals for a new floating airport in the ThamesEstuary for London offers an example of political interest in completeairport relocation.

In these busy airports, runways are managed using time slots availablefor certain weight class of aircraft. Since all time slots at congestedairports are allocated, more airplanes cannot be accommodated, so largeraircraft have been used to increase passenger and freight. Longeraircraft weigh more and produce larger wakes, potentially offsettingincreased throughput with longer time slots. The variability of aircraftweight class is one of many factors affecting the dynamics of delays fordifferent levels of utilization. As mentioned above, aircraft of heavierweight classes typically need longer runways, occupy the runway longer,but lift more mass.

New York and London regional studies estimate lost economic activity dueto limited airport capacity between $100B and $150B over ten years foreach of their regions, making the general economic benefit estimate inthe order of $10B to $15B per year. These estimates are for economicbenefits of both increased business activity and serving a growingpopulation but do not account for indirect costs the population mightincur.

The economic cost of air pollution on citizens of each city willincrease as more jet fuel is used within the confined region of theairport. Newer airplanes bring improved fuel efficiency but provideadded cargo capacity and higher thrust engines that burn more fuel onthe runway. Cleaner burning engines, while helpful, do not overcome therate of increasing demand for air travel in these highly dense andgrowing populations. In New York, new zoning allows constantly tallerbuildings to accommodate new business and apartments. Yet, the newpeople filling the taller apartments add to the overall population thatmust share a single-story runway that cannot build out or up. Recentestimates of economic costs of living with pollution in the Los Angelesregion exceed $28B per year. This is most concentrated to the east ofthe airport, but also includes pollution from all sources. Strictregulations on car emissions in the Southern California region suggestthat a significant share of this cost might come from the Los AngelesInternational Airport.

In addition to the runway constraints, the largest airports in the mostpopulated cities of the world face airspace constraints from overlappingflight paths from adjacent airports. New York's John F. Kennedy andLaGuardia along with New Jersey's Newark airports serve a largepopulation of New York City and its surrounding areas. Even as thepopulation has increased, fewer airplanes are operating throughLaGuardia due to overlapping flight paths for aircraft operating out ofNewark or John F. Kennedy. Passengers landing at JFK who need to travelto New Jersey face limited subway capacity and increasing delays due tocancellation of the subway expansion projects. In addition, attempts topush air traffic to airports in New Jersey to the north or south ofNewark face limited ground support transportation and would furtherincrease overlapping flight paths, the very reason cited for the need torelocate air traffic in the first place. In Report No. ICAT-2011-4 Feb.2011, Alexander empirically estimates the capacity of airports fromflight path data. However, outside the scope of the thesis are estimatesfor what the capacity could be within the airspace if limitations ofaircraft acceleration power were overcome.

Given the land, runway, and flight path constraints discussed above,there is a need for more efficient systems and methods for effectivelyincreasing airport throughput.

SUMMARY

Systems and methods are described for providing an electromechanicalthrust assembly. In accordance with various embodiments, theelectromechanical thrust assembly can be used to accelerate aircraftusing ground-based energy during takeoff and decelerate aircraft toabort (or reject) takeoff. In some embodiments, a system can include asled (e.g., a saddle shaped sled), an electromagnetic catapult, and anoperational control subsystem. The sled can be designed to support anaircraft or other vehicle, which can be accelerated (and possiblydecelerated) using the electromagnetic catapult along a desired path.The electromagnetic catapult (e.g., mounted to, or integrated in, anaircraft runway) can include a series of magnets, which can be activatedin a sequence to propel the sled along the desired path. The operationalcontrol subsystem is designed to provide power switching times andduration to the series of magnets, thereby creating a magnetic field tolift and accelerate the sled.

In addition, some embodiments include an energy conversion systemconnected to the electromagnetic catapult. The energy conversion systemcan convert energy from a rechargeable energy storage system intoelectricity that powers the creation of the magnetic field.

In some embodiments, a method can include positioning (e.g., using acomputer) a sled underneath a fuselage of an aircraft (e.g., with thelanding gear stowed). The computer can be used to ensure that the sledis positioned at a center of mass of the aircraft. The sled can havemultiple operating modes including a transfer mode and a takeoff mode.The sled can be expanded to grip the fuselage to prevent the aircraftfrom sliding or rotating about the center of mass during transfer andtakeoff. Then, an electromagnetic catapult can be activated toaccelerate the sled along a desired path on a ground surface. Inaddition to accelerating the sled along the desired path, the sled canbe levitated above the ground surface using magnetic forces generated bya high-density permanent magnet array. A distance between the sled andthe ground surface can be measured and used in actively adjusting themagnetic forces generated by the high-density permanent magnet array tokeep the distance between the sled and the ground surface within adesired range.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. As will be realized, theinvention is capable of modifications in various aspects, all withoutdeparting from the scope of the present invention. Accordingly, thedrawings and detailed description are to be regarded as illustrative innature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described and explainedthrough the use of the accompanying drawings in which:

FIG. 1 illustrate front and side views of a traditional support truckfor aircraft without landing gear;

FIGS. 2A-2D illustrate various operational modes of a sled which can beused in various embodiments of the present invention;

FIG. 3 is a front elevation view of an aircraft launch system inaccordance with one or more embodiments of the present invention;

FIG. 4A is a side view of an aircraft launch system with an aircraftentering the transfer station in accordance with some embodiments of thepresent invention;

FIG. 4B is a side view of an aircraft launch system in accordance withvarious embodiments of the present invention where the sled ispositioned under the aircraft;

FIG. 4C is a side view of an aircraft launch system in accordance withone or more embodiments of the present invention where the landing gearhas been stowed;

FIG. 5A is a side view of an aircraft launch system in accordance withsome embodiments of the present invention where the sled is positionedto complete transfer;

FIG. 5B is a side view of an aircraft launch system in accordance withvarious embodiments of the present invention where a transfer has beencompleted;

FIG. 6 shows a block diagram with components of an aircraft launchsystem in accordance with one or more embodiments of the presentinvention;

FIG. 7 is a flowchart with a set of operations for launching an aircraftin accordance with various embodiments of the present invention;

FIGS. 8 and 9 provide an overhead view a traditional airport and runwaylayouts;

FIG. 10 is an overhead view of the aircraft thrust system providingreduced taxi distance and ground support prior to takeoff in accordancewith one or more embodiments of the present invention;

FIG. 11 is an overhead view of a parallel topology aircraft thrustsystem in accordance with some embodiments of the present invention;

FIG. 12 is a an overhead view of a bi-directional topology aircraftthrust system in accordance with one or more embodiments of the presentinvention;

FIG. 13 is a perspective view of a staging area which may be used invarious embodiments of the present invention;

FIG. 14 is a flowchart with a set of operations for assessing charges toa customer for the utilization of an assisted takeoff system accordingto various embodiments of the present invention; and

FIG. 15 illustrates an example of a computer system with which someembodiments of the present invention may be utilized.

The drawings have not necessarily been drawn to scale. For example, thedimensions of some of the elements in the figures may be expanded orreduced to help improve the understanding of the embodiments of thepresent invention. Similarly, some components and/or operations may beseparated into different blocks or combined into a single block for thepurposes of discussion of some of the embodiments of the presentinvention. Moreover, while the invention is amenable to variousmodifications and alternative forms, specific embodiments have beenshown by way of example in the drawings and are described in detailbelow. The intention, however, is not to limit the invention to theparticular embodiments described. On the contrary, the invention isintended to cover all modifications, equivalents, and alternativesfalling within the scope of the invention as defined by the appendedclaims.

DETAILED DESCRIPTION

Various embodiments of the present invention generally relate to anelectromechanical thrust assembly. More specifically, variousembodiments of the present invention relate to systems and methods foran electromechanical thrust assembly which can be used to accelerateaircraft using ground-based energy during takeoff. By using theground-based energy system, aircraft are provided the increasedacceleration rates needed for higher takeoff velocities, and shortertakeoff lengths than possible using onboard engines and jet-fuel.

While airplanes can take off in either direction on a runway to fly intoprevailing winds, issues such as noise, pollution, and safety limit theoptions available to flight paths of the airplanes once they takeofffrom the runway. Side winds cannot be used by rotating the runway intothe wind as compared to aircraft carriers at sea, although some airportsare equipped with cross runways for these weather conditions. Withsufficient takeoff power and acceleration provided by ground energy,fewer operational constraints from wind speed and direction impacttakeoff direction decisions. Rather, pilots, and flight controllers canfly toward their flight path and experience and contribute minimally toairspace interference.

Systems that accelerate aircraft using ground-based energy exist formilitary training of aircraft carrier pilots. These designs rely uponspecially configured aircraft with reinforced landing gear and linkagesneeded for connection to the catapult shoe that travels on the flightdeck. This application provides very high force to mass ratios for highacceleration rates. Catapult acceleration forces combined with onboardengines ensure takeoff of fighter aircraft and small cargo planes withina short distance. Catapults extend the capacity of the carrier—as amobile airport—to launch heavier aircraft using less flight deck surfacearea. Aircraft carriers operate in hostile combat situations where theysupport the pilots' ability to reach and return from missions or defendthe carrier itself Civilian airspace does not contend with adjacentairports moving relative to one another. Military aircraft also containtheir own radar systems for detecting other aircraft, where civilianaircraft rely upon flight controllers using ground radar sweeps oftransponders on aircraft for location. Even with the next generation ofnavigation and airspace control, civilian aircraft will forward theirlocation to ground systems rather than operate onboard radar.

Several devices have been proposed to launch military fighter jets fromthe deck of an aircraft carrier. These involve steam, hydraulics, and/orother mechanical energy conversion systems designed to accelerate anairplane to takeoff velocity. The purpose and design of these systems,independent of energy form used, is to launch weapons for defensive oroffensive military operation. In these traditional designs, full enginethrust and full assist power is often used to overcome the need toachieve takeoff velocity over a large set of weather conditions while atsea.

Aircraft carriers often steer so that the takeoff direction fordeparting aircraft have a maximum head wind. This maximum head wind thuscreates conditions for maximum airflow into the turbine engine and overthe wings of the departing aircraft. Aircraft carriers also typicallytravel at full velocity during aircraft launch to ensure maximum headwind and ensure the lift is sufficient for flight with maximum cargoweight. In addition to adjusting the heading of the aircraft carrier,many carriers also use aircraft catapults as a form of assisted takeoff. These traditional catapult systems typically consist of a trackbuilt into the flight deck of the aircraft carrier. A large piston orshuttle is attached through the track to the nose gear of the aircraft.A release bar is often used to hold the aircraft in place as steampressure builds up. Once enough pressure has been built, the aircraft ispulled along the deck at high speed. However, steam-based and othertraditional systems currently in use are often inefficient and havelimited capabilities.

While traditional systems for providing additional acceleration toaircraft in the presence of winds have included steam-based andpulley-based catapults for accelerating aircraft. However, none of thesetraditional systems enhance throughput for the amount of mass pertakeoff per unit of time while increasing safety and reducing aviationfuel needed to begin the flight. While reducing variability of arrivaltimes of airplanes at the runway can provide for consistent queuelengths, there are two needs this does not address. First, the queuelength is more dependent upon the average capacity of the runway and thevolume of traffic demanded by the airport. Second, airplanes should waitfor runway capacity before pulling away from the gate. There is noreason aircraft must wait in a queue to takeoff, unless some eventtranspired between entering the queue and takeoff. The main cause oflong lines to takeoff is almost completely due to throughput,utilization, or average capacity of the runway. Significantly morecapacity is needed so that scheduled flights takeoff on time withoutdelay. Managing taxi time variability is less important than vastlydecreasing taxi times. A mean taxi time of thirty seconds with a verylow variability is less beneficial to passengers than a mean taxi timeof ten seconds with a very high variability.

A powered nose aircraft wheel system that can provide enough propulsionto allow the pilot to pull away from the gate without requiring groundservice equipment. In addition, the pilot could taxi using the systemeither alone if powerful enough, or with main engines for periods ofacceleration. As long as the torque provided by the motor exceeds therolling resistance of the wheels, the system would aid taxi movement.However, this type of system is not practical for the application oflaunching large aircraft due to the power needed to develop significantvelocity for lift. The use of the auxiliary power supply onboard theaircraft would only be sufficient for moving the wheel under no load topre-spin the wheel for landing. Whether the auxiliary power supply wouldprovide sufficient energy needed to power the motors in the wheels fortaxi would depend upon the rolling resistance of the aircraft, thesteering direction, and the load of the auxiliary system for otherfunctions. Obviously, if the system provides enough power to move theaircraft, the air traffic controllers can signal to the pilot to delaytaxi through telecommunication networks dedicated to FAA frequencies.The same is true for providing estimated time of arrival (ETA) at thequeue waiting for takeoff at the end of the runway used for departures.Various embodiments of the present invention obviate the need toactively manage the taxi process currently used to reduce variability inthe arrival of airplanes at the runway for takeoff.

In accordance with various embodiments of the present invention,airplanes (e.g., commercial passenger, military, unmanned airplanes, andfreight airplanes) can be loaded onto a saddle-shaped sled that supportsand balances the airplane in lieu of landing gear aboard the aircraft.The sled can be designed to levitate above the ground using high-densitypermanent magnet arrays (e.g., Halbach arrays). Then, magneticlevitation (maglev) forces may be varied along the assembly to accountfor lift provided by airflow over the wings. In addition, someembodiments provide for one or more of the following features: 1) lowemission during takeoff; 2) low noise during takeoff; 3) takeoffpropulsion without added fuel or weight to the aircraft; 4) safertakeoff operation; 5) thrust to safely overcome any single enginefailure during takeoff; 6) dramatically increase capacity of an airport,close groups of airports, and related airspace; 7) reduce taxi times;and 8) reduce the variability of process times and arrival times ofaircraft.

In various embodiments, a takeoff assist assembly is provided thatincludes energy storage, energy conversion, linkage, operational controlsubsystem, and safety systems that together provide the neededacceleration. Ground-based energy provides the electricity needed toaccelerate the airplane by use of an electromagnetic catapult mounted tothe runway. In those situations where instantaneous power available isbelow that needed during acceleration, energy storage systems capable ofhigher instantaneous power output will be used and re-charged betweentakeoffs. Sufficient energy storage at the site of launch will ensure nointerruptions of power delivered from suppliers will interfere with thesafety or schedule of the next takeoff.

Various embodiments of the present invention provide a means ofaccelerating airplanes using a ground-based energy source. The systemincludes power distribution equipment from the energy supply, gridconnection equipment where electricity supply is sufficient, or onsitegeneration. Power distribution components can be used to routeelectricity to submodules that energize sections of the electromagneticcatapult. A control system that produces the necessary power switchingtime and duration to each submodule in tandem may provide the change tothe magnetic field needed to ensure measured forces are applied to thesaddle during acceleration and during the return of the saddle to itsstarting location for repeated cycles. The control system regulatespower to ensure combined lift forces during acceleration producemagnetic levitation.

While, for convenience, embodiments of the present invention aredescribed with reference to assisted takeoffs, embodiments of thepresent invention are equally applicable to movements and vehicles. Forexample, these techniques are equally applicable to moving vehicles fromone place to another. In addition, the techniques introduced here can beembodied as special-purpose hardware (e.g., circuitry), as programmablecircuitry appropriately programmed with software and/or firmware, or asa combination of special-purpose and programmable circuitry. Hence,embodiments may include a machine-readable medium having stored thereoninstructions that may be used to program a computer (or other electronicdevices) to perform a process. The machine-readable medium may include,but is not limited to, floppy diskettes, optical disks, compact discread-only memories (CD-ROMs), magneto-optical disks, read-only memories(ROMs), random access memories (RAMs), erasable programmable read-onlymemories (EPROMs), electrically erasable programmable read-only memories(EEPROMs), magnetic or optical cards, flash memory, or other type ofmedia/machine-readable medium suitable for storing electronicinstructions.

Terminology

Brief definitions of terms, abbreviations, and phrases used throughoutthis application are given below.

The terms “connected” or “coupled” and related terms are used in anoperational sense and are not necessarily limited to a direct physicalconnection or coupling. Thus, for example, two devices may be coupleddirectly, or via one or more intermediary channels or devices. Asanother example, devices may be coupled in such a way that informationcan be passed there between, while not sharing any physical connectionwith one another. Based on the disclosure provided herein, one ofordinary skill in the art will appreciate a variety of ways in whichconnection or coupling exists in accordance with the aforementioneddefinition.

The phrases “in some embodiments,” “according to various embodiments,”“in the embodiments shown,” “in other embodiments,” and the likegenerally mean the particular feature, structure, or characteristicfollowing the phrase is included in at least one embodiment of thepresent invention, and may be included in more than one embodiment ofthe present invention. In addition, such phrases do not necessarilyrefer to the same embodiments or to different embodiments.

If the specification states a component or feature “may,” “can,”“could,” or “might” be included or have a characteristic, thatparticular component or feature is not required to be included or havethe characteristic.

The term “module” refers broadly to software, hardware, or firmware (orany combination thereof) components. Modules are typically functionalcomponents that can generate useful data or other output using specifiedinput(s). A module may or may not be self-contained. An applicationprogram (also called an “application”) may include one or more modules,or a module can include one or more application programs.

The term “takeoff” is used to refer to both the event of the takeoff andthe action to take-off as indicated by the context of the use of theterm.

General Description

FIG. 1 shows a side and front view of a traditional support truck 100for aircraft without landing gear. As illustrated in FIG. 1, the supporttruck 100 has a cavity 110, which allows the aircraft to sit within andis designed to support an aircraft during taxiing and takeoff. In somevariations of this design, the desired angle of attack of the wing maybe achieved by controlling the angle of truck 100 and an aircraftrelative to the ground. In addition, the primary source of energy fortakeoff is provided by the main onboard engines of the aircraft, whichcause wheels 120 to roll along the ground. With this approach, thedesign overcomes the limit of the fixed wing geometry by the supportproducing the same effect of slats and flaps for a typical aircraft.This is important for applications where fixed wing aircraft arerequired such as with a space shuttle.

FIGS. 2A-2D show a perspective view of various operational modes of asled 200 which can be used in various embodiments of the presentinvention. In some embodiments, a takeoff assist assembly uses groundequipment, such as sled 200, to provide the horizontal velocity neededto achieve lift. Airplanes can be transferred to sled 200 prior totakeoff. Sled 200 is designed to support the weight of the aircraftduring ground transfer and acceleration for takeoff.

In accordance with various embodiments, sled 200 can include a rigid,stationary (to the airport) sled frame 210 coupled to an aircraftsupport lever 220 having a set of wing support bags 230 and fuselagesupport bags 240. Stationary (to the airport) sled frame 210 can be madeof steel, aluminum alloys, titanium, carbon composites,fiberglass-reinforced-epoxies, and/or other plastics or metals, whichtogether provide for needed strength of joints, welds, axles, andplanes. Aircraft support lever 220 may be made of similar composites,alloy metals, and steel. In some embodiments, the fuselage and wingsupport bags can be made from synthetic rubber reinforced withhigh-strength composite mesh fabrics such as Kevlar or Nomex. It isenvisioned that the bottom of the airbags will be mechanically connectedto the sled frame.

The support lever 220 can be adjusted into different positions creatingmultiple operating modes for sled 200. These modes can include atransfer mode as illustrated in FIG. 2A, a takeoff mode as illustratedin FIG. 2B, an unlocked mode as illustrated in FIG. 2C, and a lockedmode as illustrated in FIG. 2D. The transfer mode illustrated in FIG. 2Ais designed to receive the aircraft. In some cases, sled 200 may benavigated underneath the fuselage of the aircraft to a desired position(e.g., center of mass of the aircraft). After transfer to the saddle,pilots can stow the landing gear and the operational mode of the sledcan be set to the takeoff mode. In the takeoff mode, the support lever220 can be raised so that the wing support bags 230 and fuselage supportbags 240 are fully engaged.

In addition, slat and flap settings can then be set for a takeoff giventhe weight of the aircraft, the acceleration force available from thecatapult, and any acceleration force the pilot intends to provide fromthe onboard engines. The pilot then gives the signal to catapultoperators to engage the catapult, and increases the engine thrust toproceed to vertical climb.

The two modes of the sled provide clearance between the airbags andfuselage while the aircraft is supported by landing gear. Once theaircraft arrives at the staging area via a tow truck or taxi, the sledand related support assembly are moved under the aircraft fuselage. Onceunder the fuselage, operators lock the sled into takeoff position andraise the assembly to provide support to the aircraft while landing gearis stowed. This is useful for some aircraft that have the bottom oftheir wings offset from the bottom of the fuselage. The clearance forsome aircraft may be met simply by deflating the airbags duringpositioning under the fuselage. In the event the sled assembly movedunder the aircraft can be made lower to provide the clearance viahydraulic jacks or variable magnetic force, then the sled may always beoperated in the position for takeoff.

FIG. 3 is a front elevation view of an aircraft launch system inaccordance with one or more embodiments of the present invention. Asillustrated in FIG. 3, aircraft 310 is taking off using the aircraftlaunch system. The aircraft launch system includes stationary sled frame210, aircraft support lever 220, wing support bags 230, fuselage supportbags 240, permanent magnets 320, catapult linkage 330, catapult shoe340, maglev track magnets 350, and maglev frame/catapult rail 360.

Permanent magnets 320 create a persistent magnetic field to assist inlifting sled frame 210 above maglev frame 360. In addition, the magneticfield created by the permanent magnets 320 can interact with a movingmagnetic field created by maglev track magnets 350 to accelerateairplane 310 along maglev frame/catapult rail 360. Catapult linkage 330couples sled frame 210 to the catapult shoe 340. While not illustratedin FIG. 3, some embodiments provide for multiple catapult rails 360. Thenumber of rails actively engaged can be static or dynamically determinedbased on the weight, size, type, or other characteristic of theairplane. In some cases, current weather conditions may be used todetermine how many rails are activated or used.

FIGS. 4A-4C show different views of aircraft 410 entering the transferstation of an aircraft launch system in accordance with some embodimentsof the present invention. Sled 420 in the unlocked mode is positionedunderneath aircraft 410 in a desired position. In some embodiments, sled420 may be electronically or manually controlled and assisted by acomputer to find the center of gravity 430 of aircraft 410. Sled 420 maybe designed (e.g., a saddle shape) to conform to the fuselage below thecenter of mass of airplane 410 and is coated to reduce any slidingbetween the saddle and fuselage during acceleration.

Aircraft 410 is moved from resting on its landing gear 440 to resting onthe saddle by the saddle moving from behind aircraft 410 between landinggear 440. Ground equipment drivers or automated equipment may positionsled 420 under the belly of aircraft 410 guided by computer to centerthe saddle where the center of mass resides along the length of thefuselage fore and aft. As illustrated in FIG. 4B, sled 420 transitionsfrom an unlocked operating mode to a transfer mode as the grips expandup the side of the fuselage to prevent sliding or rotation about thecenter of mass. Coating materials and vacuum created from airflowredirected during acceleration increases adhesion between the sled andfuselage. The landing gear 440 of aircraft 410 may then be retracted asillustrated in FIG. 4C to allow for efficient takeoff.

FIGS. 5A-5B illustrate side views of an aircraft launch system wheresled 510 is transferred in accordance with some embodiments of thepresent invention. As illustrated in FIGS. 5A-5B, the launch assemblycan include one or more sleds 510 and one or more maglev tracks orguideways 520 having one or more linear motors to accelerate sled 510.Airplanes 530 are loaded onto sled 510. Sled 510 may be a saddle-shapedsled or have another shape designed to support and balance airplane 530.The aircraft launch system levitates sled 510 above the ground usinghigh-density permanent magnet arrays. Magnetic levitation (maglev)forces are varied along the assembly to account for lift provided byairflow over the wings. In other embodiments, the aircraft launch systemcan levitate sled 510 using other mechanisms (or a combination ofmechanisms) for creating lift such as compressed air distributed alongthe guideway to support the sled during aircraft transfer oracceleration. FIG. 5B shows sled 510 completely transferred onto adesired guideway 520 which will guide aircraft 530 during the launch.

FIG. 6 shows a block diagram with components of an aircraft launchsystem 600 in accordance with one or more embodiments of the presentinvention. According to the embodiments shown in FIG. 6, the system caninclude memory 605, one or more processors 610, power supply 615,sensors 620, operational control subsystem 625, sled control module 630,and feedback control module 635. Other embodiments of the presentinvention may include some, all, or none of these modules and componentsalong with other modules, applications, and/or components. Still yet,some embodiments may incorporate two or more of these modules into asingle module and/or associate a portion of the functionality of one ormore of these modules with a different module. For example, in oneembodiment, operational control subsystem 625 and sled control module630 can be combined into a single module.

Memory 605 can be any device, mechanism, or populated data structureused for storing information. In accordance with some embodiments of thepresent invention, memory 605 can encompass any type of, but is notlimited to, volatile memory, nonvolatile memory, and dynamic memory. Forexample, memory 605 can be random access memory, memory storage devices,optical memory devices, magnetic media, floppy disks, magnetic tapes,hard drives, SIMMs, SDRAM, DIMMs, RDRAM, DDR RAM, SODIMMS, erasableprogrammable read-only memories (EPROMs), electrically erasableprogrammable read-only memories (EEPROMs), compact disks, DVDs, and/orthe like. In accordance with some embodiments, memory 605 may includeone or more disk drives, flash drives, one or more databases, one ormore tables, one or more files, local cache memories, processor cachememories, relational databases, flat databases, and/or the like. Inaddition, those of ordinary skill in the art will appreciate manyadditional devices and techniques for storing information which can beused as memory 605.

Memory 605 may be used to store instructions for running one or moreapplications, systems, or modules on processor(s) 610. For example,memory 605 could be used in one or more embodiments to house all or someof the instructions needed to execute the functionality of sensors 620,operational control subsystem 625, sled control module 630, and/orfeedback control module 635.

Power supply 615 can be used to provide power to the differentcomponents of the aircraft launch system. For example, power supply 615can be used to power sensors 620 and/or other components. Sensors 620can be any type of sensor for measuring environmental conditions or userinteractions. For example, sensors 620 may include one or moretemperature sensors, wind speed sensors, distance sensors, pressuresensors, magnetism sensors, and/or motion sensors. The outputs fromthese sensors can be used in computing inputs for levitating and/oraccelerating the sled to achieve a desired trajectory profile.

Some embodiments can use a calibration algorithm to ensure that themaximum acceleration rate is not exceeded during takeoff. Each sectionof the catapult will have small variations in the forces applied for agiven mass. For example, one algorithm relies upon distance sensors toadjust the force of the acceleration to ensure the desired accelerationis achieved within safe force limits of the aircraft. The measured massof the aircraft in the staging area can aid the control system ofassessing distance versus energy required for acceleration and timewindow estimate for when the system should sense takeoff and switch todeceleration of the sled.

In other embodiments, the algorithm records the energy used to achievetakeoff velocity, measured mass of the aircraft, together withtemperature, pressure, wind speed and direction, actual velocity attakeoff, aircraft slats and flaps settings to better estimate the timeof takeoff and when to deflate the airbags and decelerate the sled.These optimization computations can be multi-parameter statisticalpredictions based upon calibrated launch system measurements, model ofthe aircraft and required safety measurements.

Operational control subsystem 625 can compute power switching times andduration to be applied to magnets (e.g., electromagnets) located withthe guideways (e.g., in a linear motor). This creates a change in anelectromagnetic field created by the magnets and accelerates a sled in adesired direction along the guideways. In addition, operational controlsubsystem 625 can receive and/or transmit inputs to sled control module630. These inputs can be used to change the operational mode of the sledand/or receive information regarding the current state of the sled.Feedback control system 635 can compute the amount of power needed tomaintain the sled at a constant distance above the guideway duringacceleration.

FIG. 7 is a flowchart with a set of operations 700 for launching anaircraft in accordance with various embodiments of the presentinvention. As illustrated in FIG. 7, position operation 710 is used toposition a sled underneath the fuselage of an aircraft. In someembodiments, a computer can be used to ensure that the sled ispositioned at a center of mass of the aircraft. The center of mass maybe programmed into a database, which the computer can access. In othercases, additional measurements can be used to determine and/or refinethe center of mass of the aircraft.

The sled can have multiple operating modes including a transfer mode anda takeoff mode. Expansion operation 720 expands the sled to grip thefuselage of the aircraft. The expansion helps prevent the aircraft fromsliding or rotating about the center of mass during transfer and takeoffOnce the aircraft is secure on the sled, levitation operation 730 can beused to levitate the sled. In some embodiments, levitation operation 730can activate (e.g., open loop) a set of permanent magnets. Then, thelanding gear (if any) can be stowed during stowing operation 740.Activation operation 750 can then be used to activate an electromagneticcatapult system.

The catapult system can use levitation operation 760 to levitate thesled above one or more guides or railways at a desired distance. Variouslevitation control systems can be used to ensure that the distance ismaintained as the sled is accelerated along a desired path duringacceleration operation 770. In order to levitate and accelerate thesled, the catapult system can actively control the magnetic forcesgenerated by a high-density permanent magnet array and/or linear motors.

One advantage of using various embodiments of the present invention isthe increase in the collective capacity of one or more airports whoseassociated flight paths may overlap. In addition, taxi times may also bereduced as a result of lower process time and customer wait time.Reductions in the variability of taxi-staging-takeoff process times(e.g., as measured by the standard deviation divided by the mean) canalso be achieved.

FIGS. 8 and 9 provide an overhead view of a traditional airport andrunway layouts. In particular, FIG. 8 shows a single runway 810 havingan early runway exit 820 and taxiway 830. Planes 840 leave fromterminals 850A-850C and taxi under their own power to the runway. Thefollowing chart shows the mean taxi distance, mean taxi time, mean queuetime, takeoff duration, and the number of independent simultaneoustakeoffs of a typical airport with this traditional configuration.

Item Metric estimate source mean taxi distance ½ L derived mean taxi 960sec Best Quartile all Airlines from JFK and queue time August 2012(BTS)typical takeoff duration 42 sec derived total process time 1062 secindependent 1 observation simultaneous takeoffs

FIG. 9 shows two perpendicular runways 910 having early runway exit 920and taxi ways 930. Planes 940 leave from terminals 950A-950C and taxiunder their own power to one of the runways 910. The following chartshows the mean taxi distance, mean taxi time, mean queue time, takeoffduration, and the number of independent simultaneous takeoffs of atypical airport with this configuration.

Item metric estimate source mean taxi distance 7/9 L derived mean taxiand 1140 sec Best Quartile Delta LGA August queue time 2012 (BTS)typical takeoff duration 42 sec IATC path total process time 1282 secindependent 1 observation simultaneous takeoffs

FIG. 10 is an overhead view of the aircraft thrust system providingreduced taxi distance and ground support prior to takeoff in accordancewith one or more embodiments of the present invention. As illustrated inFIG. 10, the taxi and thrust system can include one or more stagingareas, maglev rails housed within a support beam, and a plurality ofsleds discussed above. Various embodiments provide for independentmechanisms for levitation and propulsion. High acceleration rates, highmass variability, and short duration cycles benefit from fast dischargeenergy components like flywheels controlled by localized excitationalong the rail. Magnetic levitation forces in this application start outlarge while the aircraft is stationary, but decrease nonlinearly as liftfrom the wings increases with air velocity.

The inline configuration shown in FIG. 10 includes two independentaircraft thrust system assemblies, which are configured to operate alonga line but in opposite directions. FIG. 11 is an overhead view of aparallel topology aircraft thrust system in accordance with someembodiments of the present invention. In both the embodiments shown inFIGS. 10 and 11, ground operators use staging areas to ready aircraftfor transfer to the maglev rail for takeoff. The load cells, supportingelectronics, communications and a computer system measure the locationof the center of mass of the aircraft and guide operators to properlyposition the sled under the aircraft. If the rails are oriented suchthat East faces the right side of the figure, then aircraft can takeoffin the direction most suited to the overall management of airspace andthe destination of the flight.

Each staging area 1010 illustrated in FIGS. 10 and 11 can use a transferbeam 1020 where aircraft are moved by compressed air or rollers andpowered tractor or compressed-air-powered dolly. Positioning the sled1030 under the aircraft requires location of its center of gravity. Eachstaging area houses load cells, supporting electronics, communicationsand a computer system that provide center-of-gravity location and weightmeasurements for the ground crew and pilots. The staging area providesthe ground crew with access to compressed air needed for the airbags onthe sled to support the aircraft while stowing landing gear. Inaddition, the compressed air is used to move the portable section of themaglev rail under the sled and aircraft using prior-art. Staging areas1010 may also provide de-icing infrared heaters and roofs for airportsthat experience winter weather. Controllers 1040 can be positioned toactivate the catapults upon signal from the pilots. Sled 1030 isaccelerated using takeoff assist system 1060. Once the airplane leavesthe ground, return 1070 returns the sled to one of the staging areas.

The following charts show the mean taxi distance, mean taxi time, meanqueue time, takeoff duration, time to climb out, and the number ofindependent simultaneous takeoffs of a typical airport with this inlineconfiguration.

Item Metric estimate source mean taxi distance 1/9 L derived mean taxiwait (30 mph) 36 sec derived mean maglev transfer wait 120 sec estimatemean takeoff queue wait 30 sec estimate typical takeoff duration 16 secderived total process time 196 sec independent simultaneous takeoffs 2topology

Item metric Estimate source mean acceleration 1.333 g goal V_(takeoff)208 m/s 13 m/s * 16 s, goal d_(a) 1.6 km (1.28 mi) .5 * 13 * 16² t_(d)2.1 s −10 g d_(d) 220 m .5 * 100 * 2.1² L ≈3.2 km (2.5 mi) 1.6 km * 2independent simultaneous 2 topology takeoffs time to climb out 150 s 30km/0.208 km/s

Item L ≈1.6 km (1.25 mi) 1.6 km semi-independent 2 topology simultaneoustakeoffs time to climb out ≈210 s 30 km/0.208 km/s + turnaround

Various embodiments of the present invention increase the passenger andfreight throughput of an airport's runways while requiring no additionalland. Embodiments of the takeoff assist assembly provide increased ratesof acceleration for aircraft beyond that provided by onboard engines.The higher acceleration rates allow aircraft shorter takeoff lengths andless time on the runway. The lower angle of attack required for highervelocity takeoffs reduces the wake size experienced on the runway. Inaddition, the takeoff assist assembly provides for a higher takeoffvelocity that allows aircraft to carry more total combined mass of cargoand fuel. The increased takeoff velocity allows higher lift forces fromairflow over wings while allowing for reduced drag induced from a higherangle of attacks settings for slats and flaps. Higher utilization ofaircraft leads to fewer flights needed for a given airport servicelevel, providing spare capacity and slack for bad weather conditions.

In addition to providing shorter taxi runs, aircraft no longer need totaxi to the far corners of the airport. Shorter taxi runs from terminalsto the center of the runways reduces time spent in transit to thetakeoff position which reduces fuel use, pollution and noise fromairport operations. Aircraft taxi to the center of a runway and thenenter a staging area for takeoff in one of two directions as determinedby flight paths and flight operators. The ability for aircraft totakeoff from the center of the runway allows for simultaneous takeoffsfurther increasing takeoff capacity.

By taking off from staging areas near terminals, aircraft no longer needto taxi to the far corners of the airport. The ability for aircraft totakeoff from one end of the system provides controllers the highertakeoff acceleration and shorter taxi time since even one rail isshorter than typical runways. The ability for aircraft to takeoff fromeither end of the system on one or more rails provides controllers moreflexibility in managing takeoffs, further increasing takeoff capacity.The ability for aircraft to takeoff from either end of the system on oneor more rails increases the overall capacity of the airport. The loweroverall taxi and queue duration, lower takeoff duration and lower climbduration increases the overall capacity of the airspace by decreasingthe time an aircraft spends leaving the airspace. In addition, variousembodiments provide a rate of acceleration that allows for higherairspace throughput by using higher takeoff velocities to allow pilotsto clear the general airport airspace faster than available from slowertakeoffs using onboard engines. Air traffic controllers also have moreflexibility in meeting the demand for air travel while increasingsafety. Departing aircraft have a faster climb reducing the time spentat low speeds.

FIG. 12 is an overhead view of a bi-directional topology aircraft thrustsystem in accordance with one or more embodiments of the presentinvention. Shorter, faster, and higher velocity takeoffs provided by theaircraft thrust system assembly would allow operators to resumenight-time operations by greatly reducing takeoff noise. Pilots couldengage at full throttle near takeoff and climb faster and sooner thanwithout takeoff assist, or increase thrust with altitude to maintainconstant climb and minimum ground noise. The following chart shows anestimate of the time to climb out from the bi-directional topologysystem.

Item L ≈1.6 km (1.25 mi) 1.6 km semi-independent 2 topology simultaneoustakeoffs time to climb out ≈210 s 30 km/0.208 km/s + turnaround

FIG. 13 is a perspective view of a staging area which may be used invarious embodiments of the present invention. Aircraft ready for takeoffdepart the gate and approach a staging area to prepare for takeoff asdesignated by airport tower control. As the aircraft rolls into thestaging area, load cells, supporting electronics, communications and acomputer system determine the center of mass of the aircraft. Groundservices position a maglev sled under the aircraft with guidance from acomputer system. Ground crews notify pilots of measured mass (weight)and location of the center of mass. Pilots set flaps and slats todesired takeoff velocity and notify thrust assembly controllers ofdesired takeoff velocity. Pilots stow landing gear and the aircraft ismoved to one of two thrust systems depending upon the flight path of theaircraft and designations for airspace use. Pilots notify ground thrustassembly controllers when ready for takeoff, and controllers energizethe thrust assembly to accelerate the airplane. Once close to takeoffvelocity, internal pressure inside the airbags under the aircraft on thesled falls below a threshold that triggers further deflation of theairbags and starts the deceleration process for the sled. Sledsdecelerate and disengage from the thrust assembly and then return to thestaging area to service additional flights.

As they have in the past, departing aircraft taxi from the gate wherepassengers enplane or from freight work zones. However, the staging areafor takeoff preparation bisects the maglev rail or thrust assembly.Takeoff from near the center of the airport reduces the distanceaircraft need to taxi before entering the staging area for takeoff.Other layouts allow the catapults to operate in two directions withstaging areas near terminals on opposite ends of the airport.

Aircraft traveling east will takeoff to the east from the staging area,and aircraft traveling west will takeoff to the west from the stagingarea. Or, if all aircraft takeoff to the east, then an aircraft cantakeoff using one of two thrust assemblies running roughly in parallelto each other. When coordinated across a group of airports who shareairspace, controllers can orchestrate takeoffs to minimize the need forpilots to turn around before following their more direct flight path.The ability to launch into tail winds also provides a stable operatingenvironment for takeoffs with faster climb outs and less interferencetime between departing and arriving aircraft.

FIG. 14 is a flowchart with a set of operations for assessing charges toa customer for the utilization of an assisted takeoff system accordingto various embodiments of the present invention. As illustrated in FIG.14, weighing operation 1410 weighs the aircraft of a customer that isusing an assisted takeoff system. In some embodiments, a sled within theassisted takeoff system can include a scale to determine the takeoffweight of the aircraft. Using this information, savings operation 1420can determine the fuel and/or tax savings that result from this aircraftusing the assisted takeoff system when compared to a traditionalnon-assisted takeoff. For example, since the aircraft can be acceleratedusing (completely or in part) the catapult system, there will be areduction in fuel usage, wear and tear on the engine, and possibly apotential take savings to encourage the use of the catapult system.

In addition to determining the savings that result from using theassisted takeoff systems, charging operation 1430 can determine anycharges, taxes, and/or other usage fees that need to be assessed.Computation operation 1440, then computes the total cost or charge whichshould be billed to the customer based on the savings and fees. Forexample, various embodiments allow for multiple combinations of the costsavings and fees. For example, some customers may have negotiated payinga higher percentage of the savings amount for a lower fee rate.Similarly, other customers may have negotiated paying a lower percentageof the savings amount for a higher fee amount. Still yet, some customersmay pay all of the savings in order to avoid any fees or simply payhigher fees to avoid paying any percentage of the savings. Once thetotal cost is computed, submission operation 1450 submits an invoice tothe customer for payment.

Exemplary Computer System Overview

Embodiments of the present invention include various steps andoperations, which have been described above. A variety of these stepsand operations may be performed by hardware components or may beembodied in machine-executable instructions, which may be used to causea general-purpose or special-purpose processor programmed with theinstructions to perform the steps. Alternatively, the steps may beperformed by a combination of hardware, software, and/or firmware. Assuch, FIG. 15 is an example of a computer system 1500 with whichembodiments of the present invention may be utilized. According to thepresent example, the computer system includes a bus 1510, at least oneprocessor 1520, at least one communication port 1530, a main memory1540, a removable storage media 1550, a read only memory 1560, and amass storage 1570.

Processor(s) 1520 can be any known processor, such as, but not limitedto, ARM or x86-type processors, such as an Intel® Itanium® or Itanium 2®processor(s); AMD® Opteron® or Athlon MP® processor(s); or Motorola®lines of processors. Communication port(s) 1530 can be any of an RS-232port for use with a modem-based dialup connection, a 10/100 Ethernetport, or a Gigabit port using copper or fiber. Communication port(s)1530 may be chosen depending on a network such as a Local Area Network(LAN), Wide Area Network (WAN), or any network to which the computersystem 1500 connects. The communication port 1530 may also encompasswireless communications components, such as an IEEE 802.11, 3G/4G orother wireless transceiver.

Main memory 1540 can be Random Access Memory (RAM) or any other dynamicstorage device(s) commonly known in the art. Read only memory 1560 canbe any static storage device(s) such as Programmable Read Only Memory(PROM) chips for storing static information such as instructions forprocessor 1520.

Mass storage device 1570 can be used to store information andinstructions. For example, hard disks such as the Adaptec® family ofSCSI drives, an optical disc, an array of disks such as RAID, such asthe Adaptec family of RAID drives, or any other mass storage devices maybe used.

Bus 1510 communicatively couples processor(s) 1520 with the othermemory, storage and communication blocks. Bus 1510 can be a PCI/PCI-X orSCSI-based system bus depending on the storage devices used.

Removable storage media 1550 can be any kind of external hard-drives,floppy drives, 10MEGA® Zip Drives, Compact Disc-Read Only Memory(CD-ROM), Compact Disc-Re-Writable (CD-RW), and/or Digital VideoDisk-Read Only Memory (DVD-ROM).

The components described above are meant to exemplify some types ofpossibilities. In no way should the aforementioned examples limit thescope of the invention, as they are only exemplary embodiments.

In conclusion, the present invention provides novel systems, methods,and arrangements for aircraft thrust systems. While detaileddescriptions of one or more embodiments of the invention have been givenabove, various alternatives, modifications, and equivalents will beapparent to those skilled in the art without varying from the spirit ofthe invention. For example, while the embodiments described above referto particular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations that fall within the scopeof the claims, together with all equivalents thereof. Therefore, theabove description should not be taken as limiting the scope of theinvention, which is defined by the appended claims.

What is claimed is:
 1. A takeoff control system comprising: a guideway;a sled designed to support an aircraft loaded from a staging area and tomove along the guideway, wherein the staging area includes load cells tomeasure a location of a center of gravity of the aircraft under which toposition sled; a guide to receive a sled supporting an aircraft; a firstseries of magnets configured to create magnetic forces in a sequence topropel the sled along the guideway independent of the thrust provided bythe aircraft, a second series of magnets configured to create magneticlevitation forces, wherein the magnetic levitation forces decreasenonlinearly with respect to the position in the guideway as the aircraftis lifted from the sled by airflow; and an energy storage means to powerthe first series of magnets and the second series of magnets.
 2. Thesystem of claim 1, further comprising a transfer beam to transfer theaircraft to the sled.
 3. The system of claim 2, wherein the transferbeam uses compressed air or rollers to transfer the aircraft to thesled.
 4. The system of claim 1, wherein the guideway includes a launchpath on which the airplane is accelerated by the series of magnets fortakeoff.
 5. The system of claim 1, wherein the guideway include a returnpath that returns the sled to the staging area after the airplane hasdeparted.
 6. The system of claim 1, wherein the guideway includes abi-directional topology.
 7. The system of claim 1, wherein the guidewayincludes a perpendicular topology.
 8. A method comprising: navigating anaircraft to a staging area; transferring, in the staging area, anaircraft to a sled coupled to a guideway configured to accelerate thesled using ground-based energy; expanding the sled to grip the aircraftand prevent the aircraft from sliding and rotating about the center ofmass; and activating a first series of magnets within the guideway toaccelerate the sled along the guideway, activating a second series ofmagnets within the guideway to levitate the sled upon the guideway,wherein magnetic forces created by activating the second series ofmagnets decrease nonlinearly along the guideway as the aircraft islifted from the sled during takeoff.
 9. The method of claim 7, furthercomprising using a set of sensors to measure a weight of the aircraft, acurrent air temperature, a distance to the end of the guideway, and apressure the aircraft is placing on the sled.
 10. The method of claim 7,wherein the guideway is one of multiple guideways in a perpendiculartopology or a bi-directional topology.
 11. The method of claim 10,further comprising selecting one of the multiple guideways.
 12. Themethod of claim 7, further comprising activating engines of the aircraftat full throttle during takeoff.
 13. The method of claim 7, furthercomprising increasing thrust of an engine of the aircraft with altitudeto maintain constant climb and minimum ground noise.
 14. An aircraftlaunch system comprising: a means for supporting an aircraft a guidewaycoupled to the means for supporting the aircraft and configured toautomatically accelerate an aircraft along a takeoff path and return themeans for supporting the aircraft along a return path; and a stagingarea including a transfer means for transferring the aircraft to meansfor supporting the aircraft.
 15. The aircraft launch system of claim 14,wherein the guideway includes permanent magnets and electromagnets tocreate a magnetic field moving the means for supporting the aircraftalong the guideway.
 16. The aircraft launch system of claim 14, whereinthe guideway includes one more linear motors.
 17. The aircraft launchsystem of claim 14, wherein the means for supporting the aircraftincludes one or more adjustable airbags.
 18. The aircraft launch systemof claim 14, further comprising a means for measuring an amount ofpressure the aircraft is placing on the means for supporting theaircraft.
 19. The aircraft launch system of claim 14, further comprisinga means for determining a center of gravity of the aircraft.
 20. Theaircraft launch system of claim 14, wherein the guideway includes aflywheel for accelerating the means for supporting the aircraft.
 21. Theaircraft launch system of claim 14, wherein the guideway includes ameans of storing energy.